I frequently pass by an elderly neighbor who lives in the same apartment when coming home from a dog walk. He's kind of an in-house carpenter for the building and is frequently seen around the garage. I usually just nod to him with a small murmur that sounds like こんにちは.

Now this chap is not exactly as close as a family, so ただいま doesn't quite feel right. But he's more on a talking basis rather than a higher-up, which rules out ただいま戻りました. I've seen ただいまです used in the Internets but not in spoken Japanese.

@jkerian: not sure I'm really happy with the new edited title... Both question and picked answer focussed on ただいま usage, rather than a replacement for ただいま. Which is closer to the old title than than the new... Anybody else cares to weigh in?
– DaveJun 22 '11 at 0:36

I wasn't quite happy with it either, but "Moderately polite way to say tadaima?" really didn't match where the discussion had gone. Perhaps something more along the lines of "When is tadaima appropriate?"
– jkerianJun 22 '11 at 3:55

I wasn't quite happy with the original title either, but I do think the question title should be about what the question is about, not what the whole page is about. (Here's a similar thread on meta.stackoverflow.) Because sometimes it's hard to follow a discussion if the original question context were taken away. How about: "Is there a variant of ただいま to use for a neighbor?" (dropped "polite", added "neighbor").
– entoJun 22 '11 at 16:43

4 Answers
4

It is exclusively used when arriving home (typically, when you step inside the house). Sometimes, by extension, it can be used when coming back from a trip and stepping into the airport or the train station of your destination, talking to your loved ones waiting for you (or perhaps over the phone).

As you probably know, it is usually paired with お帰り【おかえり】/お帰りなさい【おかえりなさい】 ("welcome home"), which can be used in slightly wider situations (famously, Narita airport "welcomes [foreign travellers] to Japan", but wishes "お帰りなさい" to its fellow Japanese citizen).

But in all cases, ただいま is most definitely used to address your inner circle (most typically, your companion and/or kids). Saying that to a stranger, however friendly, would be akin to saying "Honey, I'm home" to your building manager ;-)

As Mark said: こんにちは/こんばんは/おはようございます is probably the most appropriate for a friendly neighbour. On occasions, if you are coming home and he's going out, you could give him some 行ってらっしゃい【いってらっしゃい】, but this might be better left to older obaachans wishing you a nice day.

Ah, I now see the distinction between politeness and "innerness" (the ウチ(in)/ソト(out) concept). I had thought there must be an equivalent phrase for him on the politeness axis, but in fact he was on a entirely different plane. Thanks for the detailed explanation!
– entoJun 21 '11 at 12:58

As others said already, ただいま is just wrong in this situation: you're not announcing people around you in your house/lab/office that you're back, but just saluting someone who basically knows nothing about you and doesn't share any private space with you.

Appropriate greetings for this kind of encounter with your neighbourhood range from こんにちは to いい天気ですね. I consider the latter to be even better: it's not really a comment on the weather, just a way to say something when you have nothing else to say. Grandmothers meeting at bus stops are very good at sayings loads of things like that, without really engaging any conversation.

PS: you could say ただいま if you had left your neighbourhood for a few weeks, and upon meeting him, if he tells you "welcome back" during conversation.